The present invention is directed to polymers bearing groups derived from N-substituted lactams and their use as additives for improving the viscosity index and the dispersing power of lubricating oils.
From U.S. Pat. No. 3,137,222, it is known to use copolymers of methacrylates and N-vinylpyrrolidone to increase the viscosity index and the dispersing power of lubricating oils.
These copolymers are prepared by radical polymerization and, therefore, have a broad molecular distribution, making them sensitive to shear and of little effect on the thickening power or viscosity index of an oil.
By the present invention, new polymers are provided which can be used as additives to improve the viscosity index and the dispersing power of lubricating oils.
It is, therefore, an object of the present invention to provide novel polymeric additives for lubricating oils which impart excellent dispersing properties and improve the viscosity index of lubricating oils.
It is also an object of the invention to provide a novel process for producing the novel additives of the invention.
It is a further object of the invention to provide novel lubricating oils containing the novel additives of the invention.
Other objects of the invention will be apparent to those skilled in the art from the present description.